package com.gzyj.video.codec.g726;


import com.gzyj.video.codec.G711Codec;
import com.gzyj.video.codec.G711UCodec;

/**
 * G726_24 encoder and decoder.
 * <p>
 * These routines comprise an implementation of the CCITT G.726 24kbps
 * ADPCM coding algorithm.  Essentially, this implementation is identical to
 * the bit level description except for a few deviations which take advantage
 * of workstation attributes, such as hardware 2's complement arithmetic.
 * <p>
 * This implementation is based on the ANSI-C language reference implementations
 * of the CCITT (International Telegraph and Telephone Consultative Committee)
 * G.711, G.721 and G.723 voice compressions, provided by Sun Microsystems, Inc.
 * <p>
 * Acknowledgement to Sun Microsystems, Inc. for having released the original
 * ANSI-C source code to the public domain.
 */
public class G726_24 extends G726 {

    // ##### C-to-Java conversion: #####
    // short becomes int
    // char becomes int
    // unsigned char becomes int


    // *************************** STATIC ***************************

    /*
     * Maps G726_24 code word to reconstructed scale factor normalized log
     * magnitude values.
     */
    static /*short*/ int[] _dqlntab = {-2048, 135, 273, 373, 373, 273, 135, -2048};

    /* Maps G726_24 code word to log of scale factor multiplier. */
    static /*short*/ int[] _witab = {-128, 960, 4384, 18624, 18624, 4384, 960, -128};

    /*
     * Maps G726_24 code words to a set of values whose long and short
     * term averages are computed and then compared to give an indication
     * how stationary (steady state) the signal is.
     */
    static /*short*/ int[] _fitab = {0, 0x200, 0x400, 0xE00, 0xE00, 0x400, 0x200, 0};

    static /*short*/ int[] qtab_723_24 = {8, 218, 331};

    /**
     * Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.
     * Returns -1 if invalid input coding value.
     */
    public static int encode(int sl, int in_coding, G726State state) {

        /*short*/
        int sei, sezi, se, sez; /* ACCUM */
        /*short*/
        int d; /* SUBTA */
        /*short*/
        int y; /* MIX */
        /*short*/
        int sr; /* ADDB */
        /*short*/
        int dqsez; /* ADDC */
        /*short*/
        int dq, i;

        switch (in_coding) {
            /* linearize input sample to 14-bit PCM */
            case AUDIO_ENCODING_ALAW:
                sl = G711Codec.alaw2linear((byte) sl) >> 2;
                break;
            case AUDIO_ENCODING_ULAW:
                sl = G711UCodec.ulaw2linear((byte) sl) >> 2;
                break;
            case AUDIO_ENCODING_LINEAR:
                sl >>= 2; /* sl of 14-bit dynamic range */
                break;
            default:
                return (-1);
        }

        sezi = state.predictor_zero();
        sez = sezi >> 1;
        sei = sezi + state.predictor_pole();
        se = sei >> 1; /* se=estimated signal */

        d = sl - se; /* d=estimation diff. */

        /* quantize prediction difference d */
        y = state.step_size();  /* quantizer step size */
        i = quantize(d, y, qtab_723_24, 3); /* i=ADPCM code */
        dq = reconstruct(i & 4, _dqlntab[i], y); /* quantized diff. */

        sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq; /* reconstructed signal */

        dqsez = sr + sez - se;     /* pole prediction diff. */

        update(3, y, _witab[i], _fitab[i], dq, sr, dqsez, state);

        return (i);
    }


    /**
     * Decodes a 3-bit CCITT G.726 24kbps ADPCM code and returns
     * the resulting 16-bit linear PCM, A-law or u-law sample value.
     * -1 is returned if the output coding is unknown.
     */
    public static int decode(int i, int out_coding, G726State state) {

        /*short*/
        int sezi, sei, sez, se; /* ACCUM */
        /*short*/
        int y; /* MIX */
        /*short*/
        int sr; /* ADDB */
        /*short*/
        int dq;
        /*short*/
        int dqsez;

        i &= 0x07; /* mask to get proper bits */
        sezi = state.predictor_zero();
        sez = sezi >> 1;
        sei = sezi + state.predictor_pole();
        se = sei >> 1; /* se=estimated signal */

        y = state.step_size();  /* adaptive quantizer step size */
        dq = reconstruct(i & 0x04, _dqlntab[i], y); /* unquantize pred diff */

        sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); /* reconst. signal */

        dqsez = sr - se + sez; /* pole prediction diff. */

        update(3, y, _witab[i], _fitab[i], dq, sr, dqsez, state);

        switch (out_coding) {

            case AUDIO_ENCODING_ALAW:
                return (tandem_adjust_alaw(sr, se, y, i, 4, qtab_723_24));
            case AUDIO_ENCODING_ULAW:
                return (tandem_adjust_ulaw(sr, se, y, i, 4, qtab_723_24));
            case AUDIO_ENCODING_LINEAR:
                return (sr << 2); /* sr was of 14-bit dynamic range */
            default:
                return (-1);
        }
    }


    /**
     * Encodes the input chunk in_buff of linear PCM, A-law or u-law data and returns
     * the G726_24 encoded chuck into out_buff. <br>
     * It returns the actual size of the output data, or -1 in case of unknown
     * in_coding value.
     */
    public static int encode(byte[] in_buff, int in_offset, int in_len, int in_coding, byte[] out_buff, int out_offset, G726State state) {

        if (in_coding == AUDIO_ENCODING_ALAW || in_coding == AUDIO_ENCODING_ULAW) {

            int len_div_8 = in_len / 8;
            for (int i = 0; i < len_div_8; i++) {
                int value8 = 0;
                int i8 = i * 8;
                for (int j = 0; j < 8; j++) {
                    int in_value = unsignedInt(in_buff[in_offset + i8 + j]);
                    int out_value = encode(in_value, in_coding, state);
                    value8 += out_value << (3 * (7 - j));
                }
                int index = out_offset + i * 3;
                for (int k = 0; k < 3; k++) {
                    out_buff[index + k] = (byte) (value8 >> (8 * (2 - k)));
                }
            }
            return len_div_8 * 3;
        } else if (in_coding == AUDIO_ENCODING_LINEAR) {

            int len_div_16 = in_len / 16;
            for (int i = 0; i < len_div_16; i++) {
                int value16 = 0;
                int in_index = in_offset + i * 16;
                for (int j = 0; j < 8; j++) {
                    int j2 = j * 2;
                    int in_value = signedIntLittleEndian(in_buff[in_index + j2 + 1], in_buff[in_index + j2]);
                    //int out_value=encode(G711.linear2ulaw(in_value),AUDIO_ENCODING_ULAW,state);
                    int out_value = encode(in_value, in_coding, state);
                    value16 += out_value << (3 * (7 - j));
                }
                int out_index = out_offset + i * 3;
                for (int k = 0; k < 3; k++) {
                    out_buff[out_index + k] = (byte) (value16 >> (8 * (2 - k)));
                }
            }
            return len_div_16 * 3;
        } else return -1;
    }


    /**
     * Decodes the input chunk in_buff of G726_24 encoded data and returns
     * the linear PCM, A-law or u-law chunk into out_buff. <br>
     * It returns the actual size of the output data, or -1 in case of unknown
     * out_coding value.
     */
    public static int decode(byte[] in_buff, int in_offset, int in_len, int out_coding, byte[] out_buff, int out_offset, G726State state) {

        if (out_coding == AUDIO_ENCODING_ALAW || out_coding == AUDIO_ENCODING_ULAW) {

            int len_div_3 = in_len / 3;
            for (int i = 0; i < len_div_3; i++) {
                int value8 = 0;
                int in_index = in_offset + i * 3;
                for (int j = 0; j < 3; j++) {
                    value8 += unsignedInt(in_buff[in_index + j]) << (8 * (2 - j));
                }
                int out_index = out_offset + i * 8;
                for (int k = 0; k < 8; k++) {
                    int in_value = (value8 >> (3 * (7 - k))) & 0x7;
                    int out_value = decode(in_value, out_coding, state);
                    out_buff[out_index + k] = (byte) out_value;
                }
            }
            return len_div_3 * 8;
        } else if (out_coding == AUDIO_ENCODING_LINEAR) {

            int len_div_3 = in_len / 3;
            for (int i = 0; i < len_div_3; i++) {
                int value16 = 0;
                int in_index = in_offset + i * 3;
                for (int j = 0; j < 3; j++) {
                    value16 += unsignedInt(in_buff[in_index + j]) << (8 * (2 - j));
                }
                int out_index = out_offset + i * 16;
                for (int k = 0; k < 8; k++) {
                    int k2 = k * 2;
                    int in_value = (value16 >> (3 * (7 - k))) & 0x7;
                    //int out_value=G711.ulaw2linear(decode(in_value,AUDIO_ENCODING_ULAW,state));
                    int out_value = decode(in_value, out_coding, state);
                    out_buff[out_index + k2] = (byte) (out_value & 0xFF);
                    out_buff[out_index + k2 + 1] = (byte) (out_value >> 8);
                }
            }
            return len_div_3 * 16;
        } else return -1;
    }


    // ************************* NON-STATIC *************************

    /**
     * Creates a new G726_24 processor, that can be used to encode from or decode do PCM audio data.
     */
    public G726_24() {
        super(24000);
    }


    /**
     * Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.
     * Returns -1 if invalid input coding value.
     */
    public int encode(int sl, int in_coding) {
        return encode(sl, in_coding, state);
    }


    /**
     * Encodes the input chunk in_buff of linear PCM, A-law or u-law data and returns
     * the G726_24 encoded chuck into out_buff. <br>
     * It returns the actual size of the output data, or -1 in case of unknown
     * in_coding value.
     */
    public int encode(byte[] in_buff, int in_offset, int in_len, int in_coding, byte[] out_buff, int out_offset) {
        return encode(in_buff, in_offset, in_len, in_coding, out_buff, out_offset, state);
    }


    /**
     * Decodes a 3-bit CCITT G.726 24kbps ADPCM code and returns
     * the resulting 16-bit linear PCM, A-law or u-law sample value.
     * -1 is returned if the output coding is unknown.
     */
    public int decode(int i, int out_coding) {
        return decode(i, out_coding, state);
    }


    /**
     * Decodes the input chunk in_buff of G726_24 encoded data and returns
     * the linear PCM, A-law or u-law chunk into out_buff. <br>
     * It returns the actual size of the output data, or -1 in case of unknown
     * out_coding value.
     */
    public int decode(byte[] in_buff, int in_offset, int in_len, int out_coding, byte[] out_buff, int out_offset) {
        return decode(in_buff, in_offset, in_len, out_coding, out_buff, out_offset, state);
    }

}
